Audiology

Comparison of external ear resonance characteristic in a group of 7-9 year old children with A & B type tympanogram, Tehran, 1376 Hijri.

Jamileh Fatahi

Methods and Materials:This cross - sectional analytical study examines the clinical utility of the external ear resonance (EER) peak amplitude measurement as an index of the possible middle ear effusions. The EER peak amplitude and frequency of 180 ears in 98 children of 7-9 years old were recorded. 120 of them (30 girls & 30 boys) had normal hearing and showed type A tympanograms. The remomder (60 ear of 38 boys) showed type B tymoanograms. These children were examined at the clinic of audiology department, rehabilitation faculty, Tehran University of medical sciences and health services, year 1376 hijri.The tests included: 1) Otoscopy, 2) Pure tone air - condition test, 3)Tympanometry and 4) E.E.R peak amplitude and frequency measurement through test - retest.
Results: 1- The average of E.E.R peak frequency for normal hearing girls, normal hearing boys and hearing impaired boys is 3206 Hz (SD=564), 3202 Hz (SI)- 634) and 2953 (SD=37l) respectively.
2- The average of E.E.R peak amplitude is 16.0 dB SPL (SD=2.6), 16.6 dB SPL (SD= 3.0) and 23.5 dB (SD=3.0) for normal hearing girls, normal hearing boys and hearing impaired boys respectively.
3- The correlation of the mean of E.E.R peak amplitude and frequency for two normal groups, girls and boys, is not significant (p>0.0l).
4- The mean test/retest variability in the E.E.R peak amplitude is 16.0 dB SPL and 3.1 Hz for frequency. These results indicate high validity and consistency of E.E.R characteristics measurements.
5- E.E.R peak amplitude is significantly ccre1ated with the presence of type B tympanogram (p-0.00) we find a 6.9 dB SPL increase in average E.E.R peak amplitude in boys with type B tympanograms in comparison to boys with
type A results but correlation of average E.E.R peak frequency of two groups is significant too (p=0.00).
* The results are valid only within the context of this research.
* The results of this research have been compared with similar studies in abroad.

Comparing auditory discrimination in blind and sighted subjects

Sayyed Hasan Khamooshi

Studying auditory discrimination in children and the role it plays in acquiring language skills is of great importance. Also the relationship between articulation disorder and the ability to discriminate the speech sound is an important topic for speech and language researchers.Previous event- related potentials (ERPs) studies have suggested a possible participation of the visual cortex of the blind subjects were asked to discriminate 100 couple Farsi words (auditory discrimination tack) while they were listening them from recorded tape.The results showed that the blinds were able to discriminate heard material better than sighted subjects. (Prro.05)According to this study in blind subjects conical are as normally reserved for vision may be activated by other sensory modalities.This is in accordance with previous studies. We suggest that auditory cortex expands in blind humans.

Development, Standardization and Evaluation of A Close-set Speech Recognotion Test For Persian Speaking Children of 4 to 6 Years old

Mansoure Adelghahraman

Materials and Methods: This study was performed in two parts: included development and standardization of the test and the second part was the evaluation stage. In the first section, Watson&aposs crieria fpr valid speech recognition tests for children was considered. In order to balance the lists phonemically, it was necessary to determine Persian phonemes&apos frequency -of- occurences. Thus, the frequency -of- occurences for 29 phonemes of Persian language in children&aposs and adults&apos speech were separately determined. There were significant differences between some phonemes&apos frequencies in the two samples. So&apos their frequencies in children&aposs speech was used to design the test. It should be mentioned that each list could contains only 25 vowels, while almost 32 ones were meeded according to the phonemically balancing procedure. Therefore, vowels and consonants were separately balanced. The required monosyllabic words were extracted from the books written for 4 to 6 years old children. Finally, four closed set (3- picture matrix) 25 word lists were prepared. The lists were recorded on magnetic cassette in one of the IRIB studios.To assess the test validity and reliabity, 33 normal hearing children were randomly selected from kindergartens over the city of Tehranand were tested at the Audiology Clinic of the Rehabilitation Faculty, Tehran University of Medical Sciences in 1998. The tests included: otoscopy, pure tone & immittance audiometry, establishing speech reception threshold, and speech recognition test - retest by these lists.
Findings: 1- Normal hearing children obtained 92-100 percent scores for each list at their most comfortable loudness levels through test - retest.
2- No significant difference was observed in test - retest scores in each list (p>0.05).
3-No significant difference obtained between the lists test or retest scores (p>0.O5).
4-No significant difference was observed between children&aposs scores in terms of their age and gender (p>O.OS)
Conclusion: this study, therefore, is reliable and valid. The lists are phonemically balanced and equal in difficulty. Due to the conditions under which the test was designed (including, phonemic balance, necessity of using the words that could be pictured and of the presence of tow other word in children&aposs vocabulary which is similar in auditory aspects), only the content validity for word familiarity decreased a little that could be overcome by introducing them through pictures prior to the start of the test.

Frequency Distribution of Hearing Disorders among the Student of Public Elementary school in Neishaboor

Jalal Shahzadeh

Objectives: determining the frequency distribution of hearing disorders among the student of public elementary school by Otoscopy, Puretone Audiometry, Impedance Audiometiy and questionnaires.
Methods and Materials:This study was carried out in a cross - sectional descriptive survey - on 1200 students (600 girls and 600 boys) among the student of primary school of Neishabbor, academic year 1376-77
Results:1- Otoscopy examination abnormal conditions of external ear canal was found in 14.1% of cases mostly impacted ceruman (13.6%) Abnormal conditions of tympanic membrane (0.4%) and foreign body 0.16%. Abnormal conditions of external ear canal was statistically unmeaningful. (P V=0 .8)
2- Impedance Audiometiy: 5. 75% Abnormal tympanograms were observed, mostly type C (3.15%)
3- Pure Tone Audiometry: An overall 5.5% hearing loss was found in this population including 3% bilateral and 1.25% unilateral hearing loss. Only conductive hearing loss was found in this population (2.7% in right ear and 3.5% in left ear), PV=0.9.Hearing loss observed mostly in girls but the difference was slight.Family background showed no effects on the hearing disorders.9.8% of cases were in need of medical care and 0.3% were in need of rehabilitation services.Only 28.8% of parents, 36.3% of teachers and 40.9% of afflicted students were aware of the problem.

Frequency Distribution of Hearing Disorders among the Student of Public Elementary school in EslamAbad Gharb

Ahmadreza Ghasempour

Objectives :Determining the frequency distribution of hearing disorders among the student of public elementary school by Otoscopy, Puretone Audiometry, impedance Audiometry and questionnaires.
Methods and Materials: This study was can-led out in a cross - sectional descriptive survey - on 1000 students (500 girls and 500 boys) among the student of primary school of EslamAhad Gharh, academic year 1376-77
Results: 1- Otoscopy examination abnormal conditions of external ear canal was found in 13.65% of cases mostly impacted ceruman (13.3%). Abnormal conditions of external ear canal was more prevalent in girls than boys and the difference was statistically meaningful in the right (P V=0 .012) and left (PV=0.043) ear. Abnormal tympanic membrane was seen in 6.75% of cases mostly retraction (295%).
2- Impedance Audiometry: 11.05% abnormal tympanograms were observed, mostly type C (4.1%).
3- Pure Tone Audiometry: An overall 9.7% hearing loss was found in this population including 3.5% bilateral and
6.2% unilateral hearing loss. 4.15% of population suffered from SNHL observed mostly in boys and conductive. Hearing loss mostly in girls and the difference was statistically meaning in the left ear (PV=0.03).25.8% of cases were in need of medical care and surgery and six of them (l.e 0.6%) were in need of rehabilitation services.Family background showed on effects on the hearing disorders.Only 11. 4% of parents, 13.4% of teachers and 14.4% of afflicted students were aware of the problem.

Frequency analysis of normal ABR

Farajollah Okhovat Gilani

Objectives: Introducing an approach for diagnosing the normal ABR independently or supplementary used to confirm the results of the other approaches.
Materials and Methods: This study was carried out in a descriptive manner on 31 male students of audiology in the Rehabilitation Faculty which were not chosen randomly. All of the samples aged between 18 to 25 years old with normal hearing and with no history of hearing disorder. They were tested in the winter of 1377 by ABR. The resulted of their ABR tests (62 curves) were in accordance with the convenient latency norms. After the preparation stage, the frequency analysis of the curves was considered through the Fast Fourier Transform function.
Results: considering the power and phase spectrum, three components are recognized, and phase for their frequency, amplitude and phase are determined.The normative values of the obtained amounts of the frequency, amplitude and phase for the frequency analysis results of the normal ABR curves are as follows:* First Component: Frequency: 340-530 Hz, Amplitude: 23-31 dB, Phase: 0-3 radian * Second Component: Frequency: 540-370 Hz, Amplitude: 20-30 dB, Phase: 0.3-2.7 radian * Third Component: Frequency: 750-1024 Hz, Amplitude: 19-30dB, Phase: 0-3.3 radian
onclusion: The results of the present study are exclusively valid for the society being considered, and their generalization requires more researches.

Does Unilateral Hearing Loss lead to Learning Handicap?

Gita Movallali

Hearing loss, even when limited to 1 ear, has been indicatedas a handicap to communication and learning. Although thisdoes not seem true based on my clinical impressions, there areno objective data available to evaluate, or even infer, whattype of hearing loss can become a true handicap to overall academicachievement. Presented herein are findings that imply, althoughdo not prove, the potential academic handicap of unilateralhearing loss. This study prospectively analyzed the audiologicand otologic screening tests in a university over a 9-year period.The University of Tokyo is one of the leading universities inJapan the students examined undoubtedly had academic abilitywell above average, for the entrance examination is one of themost difficult to pass in Japan. The potential handicap to academicachievement caused by hearing impairment was evaluated by comparingthe prevalence of hearing impairment among the study population

Vestibular schowanoma

Massoume Rouzbahani

Vestibular Schowanoma is one of the most common Intracranial Tumors which has elicited from the Schwann cells in the upper part of vestibular branch of 8^th nerve and can affect the cochlear branch too. This benign capsulated tumor is mostly unilateral. Schowanoma is relatively slow growing.In the current article we have presented the case of a 51 year-old woman complaining Right ear Tinnitus accompanying with numbness of the right side of the face without any sign of vertigo or imbalance. MRI and Auditory Brain stem Responses (ABR) studies demonstrated right side vestibular Schowanoma next to cerebellopontine Angle (CPA). The audiological and imaging findings have been brought here in details.

Study of bone conduction of MLD test

Dr. Mohammad Reza Hadian

Materials and Methods: It is for the first time in Iran that designing and construction of phase-shifter instrument for performing Masking Level Difference have been studied. For reducing limitations of MLD test in middle ear pathologies, new methods of performing MLD has been considered.
In this method noise is conducted by bone vibrator, located on forehead. The comparison between standard method and proposed method has been obtained.Forty 20-25 year-old men referring to the Faculty of Rehabilitation Science in Iran university of Medical Sciences have been tested in the period of time between 10.30.1998 to 12.21.1998.The MLD test was performed in both method at frequencies of 250, 500, 1000, 2000 & 4000 Hz.
Results: The mean of MLD results n the standard method was 11.175 dB ranging from 10 to 13 dB that is in accordance with normative data.
- There was no significant difference between the means obtained in the methods for performing MLD.
- In both methods the MLD means decreased with frequency increments.
Conclusion: It is preferable to use proposal method in middle ear disorders due to normal cochlear sensitivity and subsequently enough noise that is conducted by bone conduction (60 dB SPL).